答案是1/2;
2013²=﹙2011+2﹚²=2011²+4×2011+4;
2013²-2=2011²+4×2011+4-2=2011²+4×2011+2;
2012²=﹙2011+1﹚²=2011²+2×2011+1;
2012²/﹙2011²+2013²﹣2﹚
=﹙2011²+2×2011+1﹚/﹙2×2011²+4×2011+2﹚
=﹙2011²+2×2011+1﹚/[2×﹙2011²+2×2011+1﹚]
=1/2
=0.5
答案是1/2;
2013²=﹙2011+2﹚²=2011²+4×2011+4;
2013²-2=2011²+4×2011+4-2=2011²+4×2011+2;
2012²=﹙2011+1﹚²=2011²+2×2011+1;
2012²/﹙2011²+2013²﹣2﹚
=﹙2011²+2×2011+1﹚/﹙2×2011²+4×2011+2﹚
=﹙2011²+2×2011+1﹚/[2×﹙2011²+2×2011+1﹚]
=1/2
=0.5